Process for producing a binding medium for colors, varnishes, and cements



Patented Feb. 28, 1928.

UNITED STATES PATENT- OFFICE.

JOHANN TENGLER, 0F TAGERWILEN, CANTON THUBGAU, SWITZERLAND.

PROCESS FOR PRODUCING A BINDING MEDIUM FOR COLORS, VARNJ ISHES, AND

, CEMENTS. v

No Drawing.. Application filed May 14, 1927, Serial No. 191,538, and in Switzerland May 11, 1926.

In my improved process utilize old rubber, such-for instance as rubber tires, tubes,

boots, or the like, and by means of my imof the old rubber, it is again'vulcanizeduniworthless. raw material varying greatly as.

formly and to the desired extent, by the addition of fresh sulphur. Thus a uniform and homogeneous product is obtained from a to degree of vulcanization and teristics.

In carrying out the process the old rubber is pulverized and placed in an autoclave'with the devulcanizing liquid. This'is preferably hydronaph-thalene. The mixture is ,subjected to pressure and heat, wherebythe other charachydrogen of the hydronaphthalene' com-- bines with the sulphur in the vulcanized rubher and separates out as hydrogen sulphide. Thereafter, a suitable solvent, such for instance as benzene, benzol, or the like, is

the whole mass. The solution is then freed added, and the necessary pressure and heat are applied to effect the complete solution of tion of sulphur or suitable shlphurpreparation. This revulcanization is effected by the application of heatan'd pressure, and is carried on to the desired extent by the control of the amount of sulphur added. A uniformity of product is thus secured,'irrespective of Wide variations in the character of the raw material, namely .old rubber, and without the necessity for analyzing or test-' ing the various lots of old rubber which are used. When the product is applied to an object the solvent rapidly evaporates, leaving the vulcanized rubber coating either to carry a color or to act as a varnish or cement.

Having thus described my invention, what I claim asnew and desire to secure by Lettors Patent is:

The process for producing a binding for colors, varnishes and cements, which consists in pulverizing old rubber, treating it with hydronaphthalene under heat and pressureto effect the formationof hydrogen sulphide and naphthalene, dissolving the resultant rubber in asolvent of lower boiling point than naphthalene, removing the naphthalene, and revulcanizing the rubber in the presence of the solvent.

JQHANN TENGLER. 

